The present invention relates, in general, to a pneumatic pressure control device for an empty/load type brake control system on a railway car, and more particularly, to a pneumatic pressure control device having a lower profile for an empty/load changeover valve on a railway car.
Prior to the present invention, an empty/load changeover valve for a railway car is typically mounted on the underside of the railway car, between the car body and the top of a horizontal surface of a railway car truck, such as a side frame. The pneumatic pressure control portion of the valve comprises a sensor arm pivot, which is located on the top of the valve. One end of a sensor arm is attached to the pivot. A sensing means is attached to the other end of the sensor arm. The sensing means is disposed on a railway car member, usually the railway car side frame, under all load conditions. An attachment disposed on the sensor arm is engageable with an actuating push rod on the empty/load changeover valve for moving the push rod in response to the sensor arm. This arrangement requires a minimum clearance of about 10xc2xd inches for proper installation and operation. Conditions that can decrease the clearance and affect the proper operation of the pneumatic pressure control device include worn truck side frame springs, or a railway car designed with truck side frame springs having a softer spring rate. Sufficient clearance requirements can also be affected by the car design and construction. If minimum clearance requirements are not maintained, the valve body can also get crushed between the railway car and the truck side frame, adversely affecting its operation.
An example of this type handbrake is taught in U.S. Pat. Nos. 5,005,915, and 5,100,207. The teachings of these references are incorporated herein by reference thereto.
In a first aspect, the present invention provides a pneumatic pressure control device for an empty/load changeover valve on a railway car, which enables an empty/load changeover valve to have a lower profile. The pneumatic pressure control devise comprises a mounting member having a first surface, a second surface, and further having an actuating push rod. A sensor arm of a predetermined size and shape has a first end and a second end. A first means is disposed adjacent at least one of the first surface and the second surface of the mounting member for pivotally supporting the sensor arm in a predetermined position on the mounting member. A second means is engageable with the sensor arm and the actuating push rod on the mounting member for moving the push rod in response to a movement of the sensor arm. A load sensing means has at least a portion thereof disposed on the second end of the sensor arm for determining a level of brake cylinder pressure required relative to an actual weight of the railway car. The sensor arm and the load sensing means have a predetermined travel limit.
In a further aspect, the present invention provides a pneumatic pressure control device for an empty/load changeover valve on a railway car, which enables an empty/load changeover valve to have a lower profile. The pneumatic pressure control devise comprises a mounting member engageable with a valve adjacent one end thereof having a first surface, a second surface, and further having an actuating push rod. A sensor arm of a predetermined size and shape has a first end and a second end. A first means is engageable with a bottom surface of a railway car for pivotally supporting the sensor arm in a predetermined position on a railway car. A second means is engageable with the sensor arm and the actuating push rod on the mounting member for moving the push rod in response to a movement of the sensor arm. A load sensing means has at least a portion thereof disposed on the second end of the sensor arm for determining a rate of brake cylinder pressure required relative to an actual weight of the railway car. The sensor arm and the load sensing means have a predetermined travel limit.
In still a further aspect, the present invention provides a pneumatic pressure control device for an empty/load changeover valve on a railway car, which enables an empty/load changeover valve to have a lower profile. The pneumatic pressure control device comprises a mounting member engageable with a valve adjacent one end thereof having a first surface and a second surface, and further having an actuating push rod. A sensor arm of a predetermined size and shape has a first end and a second end. A first means pivotally supports the sensor arm in a predetermined position on a railway car. A second means is engageable with the first end of the sensor arm and the actuating push rod on the mounting member for moving the push rod in response to a movement of the senor arm. A load sensing means has at least a portion thereof disposed on the second end of the sensor arm for determining a level of brake cylinder pressure required relative to an actual weight of a railway car. The sensor arm and the load sensing means have a predetermined travel limit.
It is therefore a primary object of the present invention to provide a pneumatic pressure control device for an empty/load changeover valve to enable the empty/load changeover valve to have a lower profile. A lower profile will allow the pneumatic pressure control device to operate in low clearance situations while minimizing the risk of potential damage to the valve.
Another object of the invention is to provide a means for mounting the device in alternate positions on a railway car to minimize or prevent damage to a valve that is typically mounted between a railway car body and a railway car truck.